This application is a 371 of PCT/FR00/03278 filed Nov. 24, 2000.
The present invention relates to novel compounds which inhibit the action of CXC chemokines, such as IL-8, Gro, NAP-2, ENA-78 etc., on their receptors, to the process for their preparation and to their use for obtaining drugs.
IL-8 (interleukin-8) is a protein of 72 amino acids belonging to the superfamily of proteins capable of attracting leukocytes, said proteins also being referred to as Cxe2x80x94Xxe2x80x94C cytokines or Cxe2x80x94C intercrine cytokines or, more recently, chemokines (Oppenheim et al., Annu. Rev. Immunol., 1991, 9, 617-648). Different names have been attributed to interleukin-8, such as NAP-1 (neutrophil attractant/activation protein 1), NAF (neutrophil activating factor) and T-cell lymphocyte chemotactic factor. Numerous members of the chemokine family have been described as being involved in inflammatory processes and leukocyte migration. The chemokine family is made up of two distinct subfamilies: alpha- and beta-chemokines. Alpha-chemokines, such as IL-8, NAP-2 (neutrophil activating peptide-2), MGSA/Gro or Gro-alpha (melanoma growth stimulatory activity) and ENA-78, all have effects on the attraction and activation of leukocytes and more particularly neutrophils. This subfamily also includes PF-4 (platelet factor-4), beta-thromboglobulin and CTAPIII, which have no effect on neutrophils.
IL-8 was originally identified by its capacity to attract and activate polymorphonuclear leukocytes (neutrophils). More recently, it was shown that the expression of IL-8 was rapidly induced in different tissues or cells, such as macrophages, fibroblasts, endothelial and epithelial cells and even neutrophils, in response to pro-inflammatory cytokines like IL-1 alpha or beta or TNF alpha, or other pro-inflammatory agents like LPS (Van Damme J., Interleukin-8 and related chemotactic cytokines; 1994; The Cytokines Handbook, 2nd ed., edited by A. W. Thomson, Academic Press, London, pp. 185-208). Furthermore, some literature data have demonstrated high systemic levels of IL-8 in certain inflammatory pathological conditions involving neutrophils, suggesting that IL-8 and other chemokines of the same family may be fundamental mediators of neutrophil activation (Van Damme, Interleukin-8 and related chemotactic cytokines; 1994; The Cytokines Handbook, 3rd ed., edited by A. W. Thomson, Academic Press, London, pp. 271-311).
Gro-alpha, Gro-beta, Gro-gamma and NAP-2 belong to the chemokine family and, like IL-8, these proteins have also been given different names. Thus Gro-alpha, beta and gamma have been called MGSA (Melanoma Growth Stimulatory Activity) a, b and g respectively (Richmond and Thomas, J. Cell Physiol., 1986, 129, 375-384; Cheng et al., J. Immunol., 1992, 148, 451-456). All these chemokines belong to the group of alpha-chemokines which possess an ELR unit (Aspartate-Leucine-Arginate) upstream of the CXC unit characteristic of this subgroup. These chemokines all bind to the type 2 receptor or CXCR2.
Two IL-8 receptors belonging to the family of receptors with seven transmembrane domains coupled to G proteins have been characterized and cloned: the type A IL-8 receptor (IL-8RA) or CXCR1, which binds IL-8 and GCP-2 with a strong affinity, and the type B IL-8 receptor (IL-8RB) or CXCR2, which has IL-8, GCP-2, Gro-alpha, Gro-beta, Gro-gamma and NAP-2 as specific ligands (Ponath, Exp. Opin. Invest. Drugs, 1998, 7, 1-18). These two receptors have an amino acid sequence homology of 77%. Numerous publications have demonstrated abnormally high levels of IL-8 in rheumatoid polyarthritis, septic shock, asthma, mucoviscidosis, myocardial infarction and psoriasis (Baggiolini et al., FEBS Lett., 1992, 307, 97-101; Mille and Krangel, Crit. Rev. Immunol., 1992, 12, 17-46; Oppenheim et al., Annu. Rev. Immunol., 1991, 9, 617-648; Seitz et al, J. Clin. Invest., 1991, 87, 463-469; Miller et al., Am. Rev. Resp. Dis., 1992, 146, 427-432; Donnelly et al., Lancet, 1993, 341, 643-647). IL-8 seems to be involved in pulmonary ischemia/reperfusion phenomena (Sekido et al., Nature, 1993, 365, 654-657). An antibody directed against IL-8, with the capacity to block the in vitro migration of rabbit neutrophils induced by IL-8, prevents the tissue damages resulting from a pulmonary ischemia/reperfusion process in the rabbit. IL-8 seems to play a major role in the changes due to myocardial hypoxia/reperfusion (Kukielka et al., J. Clin. Invest., 1995, 95, 89-103).
More recently, another study has demonstrated the beneficial effects of an IL-8-neutralizing antibody in a model of pleurisy induced by endotoxins in the rabbit (Broadus et al., J. Immunol., 1994, 152, 2960-2967). The involvement of IL-8 in pulmonary inflammations, and its deleterious role, have been demonstrated using IL-8-neutralizing antibodies in a model of pulmonary attack induced by instilling acid into rabbit""s lungs (Folkesson et al., J. Clin. Invest., 1995, 96, 107-116) and in a model of acute respiratory distress syndrome induced by endotoxins (Yokoi et al., Lab. Invest., 1997, 76, 375-384). Other reports have shown similar beneficial effects with IL-8-neutralizing antibodies in animal models of dermatosis, arthritis and glomerulonephritis (Akahoshi et al., Lymphokine and Cytokine Res., 1994, 13, 113-116; Nishimura et al., J. Leukoc. Biol., 1997, 62, 444-449; Wada et al., J. Exp. Med., 1994, 180, 1135-1140). Furthermore, mice deficient in interleukin-8 receptors have been produced by removing the gene coding for the murine IL-8 receptor homologous to the human type 2 receptor (CXCR2) (Cacalano et al., Science, 1994, 265, 682-684). Although these mice are healthy, the characteristics of their neutrophils are modified. In fact, their capacity to migrate into the peritoneum is reduced in response to an intraperitoneal injection of thioglycolate.
All these results suggest that chemokines of the IL-8 family are important mediators of the migration and activation of neutrophils and other types of cells, such as endothelial cells, in certain inflammatory conditions. Furthermore, chemokines of the IL-8 family have been described as playing an important role in tumoral growth, metastasis formation and tumoral angiogenesis in numerous types of cancer (Hebert and Baker, Cancer Invest., 1993, 11, 743-750; Richards et al., Am. J. Surg., 1997, 174, 507-512).
Study of the properties of chemokines of the IL-8 family suggests that compounds capable of antagonizing these chemokines at their receptors might have the potential to attenuate the consequences of their action in certain pathological conditions. Thus WO 96-18393 has disclosed compounds derived from 1-benzylindole-2-carboxylic acid which are capable of binding to IL-8 receptors with an inhibitory effect. More recently, according to WO 99-06354, compounds derived from urea or thiourea have also been put forward as IL-8 receptor antagonists.
The invention proposes novel non-peptide compounds which have the property of binding to the CXCR2 receptor of IL-8 and other chemokines of the same family, behaving as antagonists of these receptors.
This property of the compounds according to the invention makes it possible to envisage their use as active principles of drugs for the preventive or curative treatment of diseases involving the receptors of IL-8 and chemokines of the same family, for example rheumatoid polyarthritis, psoriasis or atypical dermatitis, diseases associated with pathological angiogenesis (such as cancer), tumoral cell proliferation and metastasis formation (for example in the case of melanoma), asthma, chronic obstruction of the lungs, acute respiratory distress syndrome, inflammation of the colon, Crohn""s disease, ulcerative colitis, gastric ulcer, septic shock, endotoxin shock, Gram-negative septicemia, toxic shock syndrome, cerebral ischemia, cardiac or renal ischemia/reperfusion phenomena, glomerulonephritis, thrombosis, Alzheimer""s disease, graft versus host reactions or allograft rejections.
According to the invention, novel compounds are proposed which have the formula 
in which:
X is a double bond xe2x80x94Cxe2x95x90Cxe2x80x94 or a sulfur atom;
R1 is a halogen, a nitro group, a trifluoromethyl group or a C1-C3 alkyl group;
R2, R3 and R4 are each independently a hydrogen atom, a halogen, a C1-C3 alkyl group, a nitro group, a trifluoromethyl group or a cyano group, or R2 and R3 form a fused aromatic ring together with the aromatic ring to which they are attached; and
n is equal to 2 or 3.
Other novel products to which the invention relates are esters of the compounds of formula I and addition salts of said compounds with a mineral or organic base.
The invention further relates to the use of a compound of formula I or salts thereof for the preparation of a drug for the preventive or curative treatment of diseases dependent on activation of the IL-8 receptors, for example rheumatoid polyarthritis, acute respiratory distress syndrome, psoriasis, Crohn""s disease and, more generally, any pathological condition associated with a massive infiltration of neutrophils.
As indicated previously, the compounds according to the invention have formula I above. According to the definitions of the substituents R1 to R4, halogen is understood as meaning fluorine, chlorine and bromine atoms, preferably fluorine and chlorine atoms. C1-C3 alkyl group must be understood as meaning methyl, ethyl, propyl, 1-methylethyl and cyclopropyl groups.
The preferred compounds of the invention are those of formula (Ia) below: 
in which:
R1 is a halogen, a nitro group, a trifluoromethyl group or a C1-C3 alkyl group;
R2 and R3 are each independently a hydrogen atom, a halogen or a C1-C3 alkyl group, or they form a fused aromatic ring together with the phenyl ring to which they are attached; and
n is equal to 2 or 3,
as well as their esters and their addition salts with a mineral or organic base.
The more particularly preferred compounds according to the invention are those of formula I in which X is a double bond xe2x80x94Cxe2x95x90Cxe2x80x94, R1 is a chlorine atom, R2 and/or R3 are each a chlorine or fluorine atom or a methyl group, preferably in the meta and/or para position of the phenyl ring, and R4 is the hydrogen atom.
Fused aromatic ring is understood as meaning a ring which, together with the aromatic ring carrying the substituents R2, R3 and R4, forms a group containing 2 fused aromatic rings, for example a 2-naphthyl or 1-naphthyl group, the 2-naphthyl group being preferred.
The compounds of formula I, which are acids, can be esterified by organic alcohols, especially C2-C3 aliphatic alcohols such as ethanol or isopropanol (or 1-methylethanol), the preferred esters being the ethyl esters.
The compounds of formula I can be salified with a mineral or organic base. Mineral bases are understood as meaning hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide, lithium hydroxide or alkaline-earth metals such as lime. Organic bases are understood as meaning primary, secondary or tertiary amines, amino alcohols, certain non-toxic nitrogen heterocycles and basic amino acids. The preferred salts are those of sodium or potassium and those of lysine, arginine or 2-amino-2-methylpropane-1,3-diol.
The compounds of formula I can be prepared in particular by a process which comprises the steps consisting in:
a) carrying out a reaction of the Friedel-Crafts type between a cyclic diacid anhydride of the formula 
in which n is equal to 2 or 3,
and an aromatic derivative of the formula 
in which X is a bond xe2x80x94Cxe2x95x90Cxe2x80x94 or a sulfur atom and R2, R3 and R4 are each independently a hydrogen atom, a halogen or a C1-C3 alkyl group, or R2 and R3 form a fused aromatic ring together with the aromatic ring to which they are attached,
in an anhydrous solvent, for example dichloromethane, in the presence of a Lewis acid, for example aluminum chloride, at a temperature of between xe2x88x9210 and +50xc2x0 C., to give a compound of the formula 
in which X, R2, R3, R4 and n are as defined above;
b) esterifying the compound of formula IV above, for example with an aliphatic alcohol of the formula ROH (R=Me or Et), under conventional conditions known to those skilled in the art, to give an ester of the formula 
in which X, R, R2, R3, R4 and n are as defined above;
c) carrying out a Fischer reaction between the compound of formula V and a phenylhydrazine of the formula 
in which R1 is a halogen, a trifluoromethyl group or a C1-C3 alkyl group, in the presence of zinc chloride, in a solvent, for example acetic acid, at a temperature of the order of 20 to 80xc2x0 C., to give the indole derivative of the formula 
in which X, R, R1, R2, R3, R4 and n are as defined above;
d) hydrolyzing the ester group of the compound of formula Ie obtained above by means of a reaction known to those skilled in the art, for example by reaction with an aqueous-alcoholic solution of sodium hydroxide, to give the corresponding acid derivative of the formula 
in which X, R1, R2, R3, R4 and n are as defined above; and
e) if necessary, preparing a salt of the acid of formula I by reacting the compound of formula I with a basic mineral or organic compound.
The compounds of formula (I) in which R1 is a nitro group can be obtained by nitrating the corresponding compounds in which R1 is hydrogen by conventional processes well known to those skilled in the art.
The compounds of formula (Ia) can be prepared by the above process using an aromatic derivative of formula (III) in which X is a double bond xe2x80x94Cxe2x95x90Cxe2x80x94, R4 is a hydrogen atom and R2 and R3 are each independently a hydrogen atom, a halogen or a C1-C3 alkyl group or form a fused aromatic ring together with the phenyl ring to which they are attached.
The above-mentioned compounds of formula (V) can also be obtained directly by carrying out a reaction of the Friedel-Crafts type between an acid chloride of the formula 
and an aromatic derivative of formula (III) as defined above.
One variant of the process for the preparation of the compounds of formula I comprises carrying out the reactions consisting in:
a) introducing a bromine atom into the 2-position of an indole derivative of formula VII: 
in which R is a methyl group, R1 is a halogen, a trifluoromethyl group, a nitro group or a C1-C3 alkyl group and n is 2 or 3,
especially by reaction with N-bromosuccinimide, in a solvent such as carbon tetrachloride, to give the compound of the formula 
in which n, R and R1 remain unchanged;
b) introducing a substituted or unsubstituted aromatic group to replace the bromine atom in the 2-position of the compound of formula VIII, especially by reaction with a boronic acid of the formula 
in which R2, R3 and R4 are each independently a hydrogen atom, a C1-C3 alkyl group, a chlorine atom, a fluorine atom, a trifluoromethyl group or a cyano group and X is a double bond xe2x80x94Cxe2x95x90Cxe2x80x94 or a sulfur atom,
in a solvent, in the presence of a catalyst such as tetrakis(triphenylphosphine)palladium, to give a compound of the formula 
in which X, R, R1, R2, R3, R4 and n are as defined above; and
c) hydrolyzing the ester group of the compound of formula Ie, by a procedure analogous to that recommended in stage d) of the process described above, to give the compound of formula I: 
in which X, R1, R2, R3, R4 and n are as defined above.
In one variant of this process, step b) consists in reacting the compound of formula VIII with a tin derivative containing a nitrated aromatic ring, for example trimethyl(4-nitrophenyl)tin, by conventional processes well known to those skilled in the art, to form the compounds of formula (I) in which R2, R3 or R4 is a nitro group.
A suspension of 2.59 g (19.4.10xe2x88x923 mol) of aluminum chloride in 4 ml of dichloromethane is prepared. It is cooled to xe2x88x925xc2x0 C. and a mixture of 0.97 ml (10.3.10xe2x88x923 mol) of fluorobenzene and 1.31 ml (8.4.10xe2x88x923 mol) of methyl 6-chloro-6-oxohexanoate in 3 ml of dichloromethane is added gradually, the temperature being maintained between xe2x88x924 and xe2x88x927xc2x0 C. The temperature is then allowed to rise to 20xc2x0 C. and, after 15 hours, the mixture is hydrolyzed in acidified iced water. It is extracted with dichloromethane and the organic phase obtained is washed with water, dried over magnesium sulfate and concentrated under reduced pressure. The 2 g of crude product recovered in this way are purified by chromatography on silica gel using a petroleum ether/ethyl acetate mixture (96/4) as the eluent to give 1.26 g of the expected product in the form of a white powder (yield=63%).
M.p.=58-59xc2x0 C.
The expected product is obtained in the form of an ochre solid with a yield of 79% by following a procedure analogous to Preparation I and starting from 1,2-dichlorobenzene.
M.p.=41-44xc2x0 C.
The expected product is obtained in the form of a beige solid with a yield of 53% by following a procedure analogous to Preparation I and starting from naphthalene.
M.p.=58-60xc2x0 C.
A suspension of 22.32 g (0.167 mol) of aluminum chloride in 35 ml of dichloromethane is prepared. It is cooled to 0xc2x0 C. and a mixture of 8.3 g (0.0728 mol) of glutaric anhydride (dihydro-2H-pyran-2,6(3H)-dione) and 8.4 ml (0.0895 mol) of fluorobenzene in 20 ml of dichloromethane is added slowly. The mixture is stirred for 15 hours at room temperature and then hydrolyzed in acidified iced water. The precipitated product is filtered off, washed with water and then dried under reduced pressure. The crude product is then recrystallized from 90 ml of ethyl acetate to give 8.8 g of the expected product in the form of beige crystals (yield=57.5%).
M.p.=134-136xc2x0 C.
The expected product is obtained in the form of a brown solid with a yield of 39% by following a procedure analogous to Preparation IV and starting from chlorobenzene.
M.p.=108-110xc2x0 C.
The expected product is obtained in the form of a beige solid with a yield of 34% by following a procedure analogous to Preparation IV and starting from toluene.
M.p.=131-133xc2x0 C.
A suspension of 8.76 g (41.7.10xe2x88x923 mol) of the acid obtained according to Preparation IV in 80 ml of ethanol is prepared and 1.33 ml of pure sulfuric acid are added. The mixture is refluxed for 5 hours, with stirring. The reaction medium is subsequently concentrated under reduced pressure and then taken up in ethyl ether. This organic phase is washed with water, then with dilute sodium hydroxide solution and then again with water. After drying over magnesium sulfate, the solvent is driven off under reduced pressure to give 9.65 g of the expected product in the form of a pale orange solid (yield=97%).
M.p.=46-47xc2x0 C.
The expected product is obtained in the form of a brown solid with a yield of 87% by following a procedure analogous to Preparation VII and starting from the acid obtained according to Preparation V.
M.p.=45-48xc2x0 C.
The expected product is obtained in the form of a brown solid with a yield of 65% by following a procedure analogous to Preparation VII and starting from the acid obtained according to Preparation VI.
M.p.=36-38xc2x0 C.